Log4j 2 SLF4J绑定和Log4j 2到SLF4J适配器有什么区别

Question

As the title, what is the difference between 2 of them.

And when is better to use Log4j 2 SLF4J Binding, and when is better to use Log4j 2 to SLF4J Adapter?

Answer 1

Its simple really.

The log4j2-slf4j binding log4j-slf4j-impl-2.3.jar routes calls from slf4j to log4j2.

This is the most common usage case. It allows you to code your application with slf4j API but use log4j2 as the underlying implementation.

The log4j2 to slf4j adapter log4j-to-slf4j-2.3.jar does the opposite it routes calls from log4j2 to slf4j.

This is much less commonly used for log4j2 but more so for older frameworks. It is useful whenever you have an existing application coded using the log4j2 framework but wish to use another framework. By using this adapter you route calls from log4j2 to slf4j. slf4j can then route those calls to any compatible implementation as discussed in the first case.

Ideally you always want the first case since it is more straight forward and efficient. However it may require much more refactoring than the second if working with an existing implementation of logging